The present invention relates to an automotive compressor, in particular for supplying pressurized fluid to fuel cell systems.
Automotive centrifugal compressors are known which substantially comprise a fixed portion, and one or more bladed impellers driven by an external motor. The fixed portion is normally defined by a hollow casing, in which the impeller rotates to produce the desired compression of the fluid flowing through it.
More specifically, the casing defines, integrally, an intake section through which the fluid to be compressed is fed to the impeller to increase its kinetic energy; and a delivery section defined by a diffuser, in which the kinetic energy is converted to pressure energy.
The intake section may have a number of fixed blades acting as a distributor, i.e. defining respective channels of given shape to conduct and accelerate the fluid intake onto the impeller in the desired direction of impact on the impeller blades.
In other words, the fixed blades substantially provide for imparting to the fluid for compression an optimum direction of impact on the movable blades of the impeller, so as to reduce fluid-dynamic losses and improve the overall efficiency of the compressor.
Fuel cell drive systems require compressor impellers of variable geometry, both for test purposes and to permit a certain amount of flexibility in the equipping of different types of vehicles.